a. Field of the Invention
This invention relates to an automatic printing apparatus, and more particularly to an automatic printing apparatus which can automatically and continuously execute a sequence of printing and treating processes from the formation to the printing of an image formation member having an image pattern already formed thereon which may repetitively be subjected to the image reproducing process (hereinafter referred to as the master).
The term "image formation member" used herein means a member having no image pattern formed thereon which may repetitively be subjected to the image reproducing process.
The term "master" used herein means a member having an image pattern already formed thereon which may repetitively be subjected to the image reproducing process.
b. Description of the Prior Art
In the age of information like now, ways of communication are more and more diviersified and correspondingly, the paper work as means of communication inside and outside offices is not only in the tendency toward increased quantities of copies (duplicates and prints) and increased copy cost, but also strong demand for higher copying speed and higher quality of copies comes from the user and there is a great desire for the exploitation of an apparatus for reproducing image originals such as documents and the like which is endowed with various desirable properties such as high speed, conformability, instantaneity, high reliability, ease of maintenance, etc.
In answer to such desire, there have been exploited or proposed various apparatuses in the fields of copying and printing. One of them is a printer which is equipped with an image reproducing process unit capable of executing an image reproducing process like the electrostatic printing process for forming duplicates of original documents on paper or the like. Such printer usually includes a master preparation process section and a plurality of process sections which may execute their functions when predetermined processing operations such as electrical charging, development, image transfer, fixation, etc. are to be carried out for the image reproducing process.
The master usable with such a printing apparatus may be one formed as by an electrically insulative substance such as synthetic resin or the like provided on an electrically conductive substrate and having an image pattern formed thereon corresponding to the image of an original document to be reproduced, or one having such an image pattern formed on a metal sheet by the use of photoresist, photopolymer or the like, or one having an electrically insulative resin image formed as on a copy sheet of zinc oxide through the known electrophotographic process and the image pattern on any of these masters may be repetitively subjected to the image reproducing process.
However, the process of forming and treating these masters includes a number of steps and is often cumbersome and complicated and time-consuming because it includes the wet type treatment, and therefore the printing apparatus including a process section for executing the treating process for forming such as master is poor in instantaneity, conformability, operability, simplicity, etc. Further, a printing apparatus using the copy sheet of zinc oxide involves a number of steps because the formation and treatment of the master therein includes procedures such as charging, exposure, development, fixation, etc. and moreover, the process arrangement having process sections for executing these processes is not often permitted to serve also as the process arrangement having process sections executing the procedures such as charging, development, image transfer, fixation, etc. which are involved in the electrostatic printing process, and accordingly, an independent section for forming and treating the master must be added, thus generally increasing the size of the apparatus. Furthermore, a master made from a copy sheet of zinc oxide essentially creates a fog potential which results in creation of the ground fog in the reproduced image (duplicate image). Thus, it is necessary during the execution of the electrostatic printing process that the step of applying the procedure of whole surface exposure be added before the developing step is executed, or that the step of applying a bias voltage higher than usual be added during the developing step, and also that some countermeasure be taken to overcome the disadvantage resulting from the presence of electrical resistance spots on the photosensitive layer of zinc oxide resin or its back-up member which is paper, which resistance spots may often appear conspicuously in the form of density spots in the optical density half-tone region of a reproduced image when provided as the result of the electrostatic printing process. Therefore, it is further necessary to provide a processing section which may be accurately controlled to execute these procedures.
In addition, the image pattern on any of the above-described masters is formed by concavo-convexity and when repetitively subjected to the electrostatic printing process, the concavo-convex surface of the master may be injured by mechanical friction so that the image pattern may be disturbed or may create spots of charge, with a resultant problem that the quality of the reproduced image may be reduced in accordance with the frequency with which the electrostatic printing process is repeated for the same master.
Furthermore, the printing apparatus so far described requires professional technique for adjusting and operating the processing sections executing the formation and treatment of a master, which in turn leads to the necessity for a highly trained professional operator to take in charge of the apparatus.
As noted above, the printing apparatus of the prior art may not be said to sufficiently meet the user's desire in respect of the problems concerning the master preparation and treating process and adjustment and operation of the process section therefor, as well as the problem concerning the master so formed.